diff -r 7c593d4f1f89 -r d562c9948dee src/HOL/Tools/Quickcheck/narrowing_generators.ML
--- a/src/HOL/Tools/Quickcheck/narrowing_generators.ML	Mon Jun 06 21:28:45 2016 +0200
+++ b/src/HOL/Tools/Quickcheck/narrowing_generators.ML	Mon Jun 06 21:28:46 2016 +0200
@@ -111,7 +111,7 @@
   in
     thy
     |> Code.del_eqns const
-    |> fold Code.add_eqn eqs
+    |> fold (Code.add_eqn (Code.Equation, false)) eqs (*FIXME default code equation!?*)
   end
 
 fun ensure_partial_term_of_code (tyco, (raw_vs, cs)) thy =